Protein enrichment of apple pomace and use in feed for Nile tilapia.

The purpose of this paper is to investigate the protein enrichment of apple pomace by Gongronella butleri through solid-state cultivation and addition of this material as feed for tilapia fry (Oreochromis niloticus). Factorial experimental design was used for the assessment of culture conditions to determine the effects of the source of nitrogen, initial moisture, and granulometry on the protein enrichment of apple pomace. During culture, the consumption of reducing sugars and the production of soluble protein were determined. The best conditions obtained were with urea (5% w/w), initial moisture of 70% and granulometry in the range from 0.85 to 1.70 mm, producing 19.63% of soluble protein. The fry submitted to the diet containing treated apple pomace presented an increase of 44% in body mass, demonstrating that apple pomace biotransformed may represent an excellent food supplement.

Apple pomace: a versatile substrate for biotechnological applications.

Apple pomace is the processing waste generated after apple juice manufacturing and represents up to 30% of the original fruit. This solid residue consists of a complex mixture of peel, core, seed, calyx, stem, and soft tissue. This residual material is a poor animal feed supplement because of its extremely low protein content and high amount of sugar. The application of agroindustrial by-products in bioprocesses offers a wide range of alternative substrates, thus helping solve pollution problems related to their disposal. Attempts have been made to use apple pomace to generate several value-added products, such as enzymes, single cell protein, aroma compounds, ethanol, organic acids, polysaccharides, and mushrooms. This article reviews recent developments regarding processes and products that employed apple pomace as a substrate for biotechnological applications.